Calk for golf shoes

ABSTRACT

A calk to be mounted on the sole of a golf shoe, wherein the central spindle is made of a semi-hard steel containing about 0.45 percent of carbon and only the portion of said central spindle projecting below the base plate thereof is made to have a high hardness by quenching.

O Unlted States Patent [1 1 1111 3,828,364 Aoyama Aug. 13, 1974 CALK FORGOLF SHOES 3,423,855 1/1969 Kosono 36/67 D [75] Inventor: Yahyo Aoyama,Tokyo, Japan FOREIGN PATENTS OR APPLICATIONS [73] Assignee: MiyataKinzoku Kogyo Kab hiki 673,399 6/1952 Great Britain 36/67 D Kaisha,Tokyo, Japan P Ex R h d J S I rimary amineric ar can an, Jr. 2 1973Attorney, Agent, or Firm-Woodhams, Blanchard and 21 Appl. No.2 392,747Flynn 52 0.5.01. ..36/67B [57] ABSTRACT [51] Int. Cl A44b 21/00 A a tobe mou ted on the ole of a g shoe, [58] Field of Search 36/67 R, 67 B,2.5 AH, h n th entral spindle is made of a semi-hard 36/59; 12/146 steelcontaining about 0.45 percent of carbon and only the portion of saidcentral spindle projecting [56] References Cit d below the base platethereof is made to have a high UNITED STATES PATENTS hardness byquenchmg- 7/1959 Melchiona 36/67 B 6 Claims, 7 Drawing Figures PAIENIEUAUGI 31974 FIG. |B

FIG. IA

FIG. 6

1 CALK FOR GOLF SHOES BACKGROUND OF THE INVENTION in that the calkmounted on the sole of it gets quickly worn down and rounded off tobecome useless as a spike.

With a view to minimizing this wear, there have hitherto been proposedvarious golf shoes such as employing a calk prepared by forming it witha mild steel and hardening thereafter in its entirety, or a calkprepared by hardening only the portion 1 of the central spindle as shownin the appended FIG. 1A, or a calk wherein only the tip 3 of the centralspindle is provided inserted therein with the core 2 having highhardness as shown in FIG. 18.

However, those calks in the prior art have all been defective in that,in the case of the calk made of mild steel and subjected to hardening inits entirety, the base plate portion is apt to break and fall offrendering it impossible to remove the central spindle from the sole, inthe case of the calk of FIG. 1A wherein only the central spindle hasbeen subjected to hardening, the thickness of the portion 1 having highhardness is not sufficient so that the calk is apt to quickly wear downby the tip of calk and the effect of the hardening cannot be muchexpected, and in the case of the calk of FIG. 1B wherein the core 2having high hardness has been inserted in just the tip of the centralspindle, the portion 3 made of iron to hold said core 2 is apt to weardown and the degree of wearing of this portion is especially high due toits poor thickness, said wearing of the portion 3 holding the core 2causing the latter to slip out of the former, thereby making the calkuseless. Not only that, inasmuch as said core 2 is usually made of analloy of superhigh hardness such as tungsten carbide, it is expensiveand not easy to work thereupon.

SUMMARY OF THE INVENTION The present invention is intended to make upfor the foregoing defects of the calks in the prior art and to provide acalk having the hereunder described characteristic features. To beprecise, one object of the present invention is to provide a calkwherein the central spindle consists of a semi-hard steel containingabout 0.45 percent of carbon so as to prevent occurrence of troubles notonly in cutting the male screw thread to be provided for the upper halfof the central spindle but also in the working for fixing the centralspindle onto the base plate by calking or stamping a trade mark and thelike onto the lower end of the central spindle. Another object of thepresent invention is to provide a calk having a very high abrasionresistance and a lasting effect of spike through the processcharacterized by that, subsequent to the foregoing working upon thecentral spindle, the portion of the central spindle pro- BRIEFDESCRIPTION OF THE DRAWINGS In the appended drawings:

FIG. 1A is a front view of the vertical section of the first embodimentof a calk in the prior art to be mounted on the sole of a golf shoe;

FIG. 1B is a frontview of the second embodiment of a calk partly brokenaway in the prior art to be mounted on the sole of a golf shoe;

FIG. 2 is a perspective view of the central spindle relevant to a calkaccording to the present invention;

FIG. 3 is a perspective view of the base plate relevant to the same calkas that in FIG. 2;

FIG. 4 is a perspective view of the same calk as assembled as that inFIG. 2;

FIG. 5 is a front view of the vertical section of the same assembledcalk as that in FIG. 4; and

FIG. 6 is a plan view as taken from the bottom side of the same calk asthat in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION Referring to the embodiment of thepresent invention shown in FIGS. 2, 3, 4, 5 and 6, a calk for the golfshoe under the present invention consists of the central spindle l0 andthe base plate 20.

The central spindle 10 consists of a semi-hard steel containing about0.45 percent of carbon, the upper end of said central spindle beingprovided with the male screw 11 for the purpose of fixing it onto thesole of golf shoe by screwing, the middle portion of said centralspindle being formed into an elliptic shaft 12 thicker than said malescrew 11 so as to fit in the elliptic central hole 21 of the base plate20 and also being provided with the flange 13 formed beneath saidelliptic shaft 12 so as to seat the base plate thereon, and the lowerhalf 14 of said central spindle being formed into an inverted cone, soas to comprise a spike.

The base plate 20 is made of a mild steel plate and is shaped in theform of a slightly concave disc whose center is provided with saidelliptic hole 21 where said elliptic shaft 12 of the central spindle 10is supposed to fit in. In this connection, the small holes 22, 22 boredin this base plate on both sides of said elliptic hole 21 are for thepurpose of putting two ends of a tool for driving the screw 11 at thetime of mounting the calk on the sole of a shoe.

When the upper half of the central spindle 10 is fitted in the elliptichole 21 of the base plate 20 from the bottom side of said plate, theelliptic shaft 12 fits exactly in said hole 21 and the base plate 20 isseated on the flange 13. Upon this, when two side edges 15, 15 of theelliptic shaft 12 projecting above the surface of the base plate 20 arecalked on the base plate 20 in such a fashion as shown in FIG. 5, thecentral spindle l0 and the base plate 20 come to conjoin securely to beno longer detachable. As a calk according to the present invention isassembled as above and, by virtue of the elliptic hole 21 and theelliptic shaft 12, it never permits free rotation of the central spindle10 relative to the base plate 20, it can be firmly fixed on the sole ofa golf shoe by intensely turning the base plate 20.

The elliptic shaft 12 according to the present invention has a meritthat it renders it possible to perform the work of calking or deformingsame without inflicting any damage on the male screw 11, and the heightof the elliptic shaft 12 is such that it just slightly exceeds thethickness of the base plate 20 and does not stick out of the level ofthe rim of the concave base plate 20;

According to a calk under the present invention as assembled as above,the trade mark is stamped on the surface of the lower end of the centralspindle 10, the lower half or spike 14 of the central spindle 10projecting below the base plate 20 is red-heated up to more than about900 C by a high-frequency heater andv cooled with water immediatelythereafter to effect quenching. In the case of a semi-hard steelcontaining about 0.45 percent of carbon employed for the presentinvention, as a result of said quenching, a greater part of the tip ofsaid lower half 14 as denoted by a in FIG. 5 gets hardened to bepossessed of a superb abrasion resistance. Accordingly, in the casewhere the present calk is applied to the sole of a golf shoe, the degreeof wear thereof at the time of walking on gravel roads or concretefloors can be minimized and a lasting effect of spike can be expected.

In this connection, inasmuch as the exclusive application ofhigh-frequency heating to the lower half 14 of the central spindle hasno effect of quenching the base plate 20, there is no fear of causingthe base plate 20 to harden or break. Besides, a semi-hard steelcontaining about 0.45 percent of carbon employed for the central spindlel facilitates such workings as cutting of the male screw 11, calking andstamping of the trade name 16 as long as it retains a normal mildness,and therefore, it not only is very convenient for the present inventionin this respect but also renders it possible to produce a durable calkfor the golf shoe economically.

What is claimed is:

1. In a calk for a golf shoe having a central spindle defining an upperthreaded portion and a lower conical portion forming a spike, and anenlarged concave base plate surrounding a central portion of saidspindle and fixed relative thereto, comprising the improvement whereinsaid spindle is of a semi-hard steel and is solid throughout the lengththereof, only said spike being heat hardened, said spindle having thecentral portion thereof formed with an elliptical cross section, saidspindle also having a shoulder formed between said spike and saidcentral portion of elliptical cross section, said base plate having acentral opening of substantially elliptical shape, said base plate beingseated on said shoulder with said central portion extending through saidopening, said central portion having a thickness greater than thethickness of said plate, and the edges of said central portion beingdeformed downwardly over said base plate for fixedly and nonrotatablyconnecting said base plate to said spindle.

2. A calk according to claim 1, wherein the spindle is made from asemi-hard steel containing approximately 0.45 percent carbon, and thespike being hardened by heating only said spike to a temperature of atleast 900 C and thereafter quenching the spike.

3. A method for forming a calk for a golf shoe having a central spindledefining an upper threaded portion and a lower conical portion defininga spike, and an enlarged base plate fixed to said spindle andsurrounding a center portion thereof, comprising the steps of providinga solid shaftlike member formed of a mild steel containing approximately0.45 percent carbon, forming a conical portion on the lower end of saidmember so as to define said spike, said spike being solid, providing anenlarged base plate having a central opening therethrough, positioningsaid base plate in surrounding relationship to a center portion of saidmember, fixedly connecting said base plate to said member by causingrelative physical deformation between said base plate and said member,and hardening only said spike by heating said spike to a temperature ofat least 900 C and then quenching said heated spike to harden same.

4. A method according to claim 3, wherein the hardening of said spikeoccurs after said base plate has been fixedly connected to said member.

5. A method according to claim 4, including the step of threading theupper portion of said member before hardening said spike.

6. A process according to claim 3, wherein said spike is hardened byheating same with a high frequency heater so as to heat only said spiketo the desired temperature, and therafter immediately water quenchingsaid spike.

1. In a calk for a golf shoe having a central spindle defining an upperthreaded portion and a lower conical portion forming a spike, and anenlarged concave base plate surrounding a central portion of saidspindle and fixed relative thereto, comprising the improvement whereinsaid spindle is of a semi-hard steel and is solid throughout the lengththereof, only said spike being heat hardened, said spindle having thecentral portion thereof formed with an elliptical cross section, saidspindle also having a shoulder formed between said spike and saidcentral portion of elliptical cross section, said base plate having acentral opening of substantially elliptical shape, said base plate beingseated on said shoulder with said central portion extending through saidopening, said central portion having a thickness greater than thethickness of said plate, and the edges of said central portion beingdeformed downwardly over said base plate for fixedly and nonrotatablyconnecting said base plate to said spindle.
 2. A calk according to claim1, wherein the spindle is made from a semi-hard steel containingapproximately 0.45 percent carbon, and the spike being hardened byheating only said spike to a temperature of at least 900* C andthereafter quenching the spike.
 3. A method for forming a calk for agolf shoe having a central spindle defining an upper threaded portionand a lower conical portion defining a spike, and an enlarged base platefixed to said spindle and surrounding a center portion thereof,comprising the steps of providing a solid shaftlike member formed of amild steel containing approximately 0.45 percent carbon, forming aconical portion on the lower end of said member so as to define saidspike, said spike being solid, providing an enlarged base plate having acentral opening therethrough, positioning said base plate in surroundingrelationship to a center portion of said member, fixedly connecting saidbase plate to said member by causing relative physical deformationbetween said base plate and said member, and hardening only said spikeby heating said spike to a temperature of at least 900* C and thenquenching said heated spike to harden same.
 4. A method according toclaim 3, wherein the hardening of said spike occurs after said baseplate has been fixedly connected to said member.
 5. A method accordingto claim 4, including the step of threading the upper portion of saidmember before hardening said spike.
 6. A process according to claim 3,wherein said spike is hardened by heating same with a high frequencyheater so as to heat only said spike to the desIred temperature, andtherafter immediately water quenching said spike.